DerekL1963

1 - a scientific experiment to find out... what? 3 - There were no ships inbound to Venus they could ride home? That makes no sense whatsoever. You haven't solved the bottleneck problem - because your system is designed to produce scientists. The bottleneck isn't in luxuries - it's in necessities, the engineers and technicians needed to operate and maintain the machinery. An element that's in high demand (and completely irreplaceable) that suddenly become rare enough on Earth that they think it's worth it dredge it from the surface of Venus... And yet it's not found someplace easier to get to like the Moon or the asteroids? That's a tall order for a McGuffin.

And those current settlements have something the notional Venus colony does not have - a connection to the outside world. Things they don't produce come to the town, and specialists they don't have can either come to the town (well drillers say) or they can travel to the specialists (doctors, etc...). They are not, as the OP desires his colony to be, fully self sufficient.

More noodling about with research in preparations for my Jool-5 run. I've got all my landers down pat, and am ready for my first dress rehearsal. (Details in my Jool 5 log.) Tonight's beauty shot - a mockup of the entire assembly (sans main propulsion) in orbit around Jool and ready to start my dress rehearsal. Well, dangit, either the forum or Photobucket isn't playing nice right now. The pic can be seen in the Jool 5 log.

Update: 09/29/2016 Just out of curiosity, I decided to see if my Tylo/Vall/Bop lander (last seen docked to the "mothership") could make it to Pol, land, and return. To my great surprise, it did so - though it was a nail biter, as it docked back at the mothership with less than 200 m/s (less than 10%) delta-V remaining. So, now it's the Tylo/Vall/Bop/Pol lander - and I can cover all of Jool's moons with just two landers. (The second you will recall is for Laythe.) That;s pretty cool if I do say so myself. And I'm pretty pleased that I've now landed on all five of the Joolian moons, leaving Gilly and Eeloo as the only solid bodies I haven't landed on. (Though I have lithobraked on Gilly.) I think Eve and Dres are the only bodies I've landed on that I haven't also taken off from. I've only ever returned (from outside Kerbin's SOI) from Duna and Moho though. Both the Bop and Pol returns shaved it a bit close, so I'm pondering on adding a small LFO pod they can dock to and cart along. The last task of the night was assembling this monstrosity, a mockup of the entire assembly. 256 tons in total (though 40 odd of that is the T/TV) will all the hardware needed to execute the mission. The plan is to execute a complete (unkerbaled) dress rehearsal of the entire mission, mostly to validate my fuel requirements but also to work out my mission techniques. (The radial orange tanks are LFO for refueling the landers, the core is LF only for refueling the T/TV.) Hopefully I'm carting around too much fuel and can trim that weight back some. Once the dress rehearsal is done, then I'm ready to figure out how to move the entire SOB from Kerbin to Jool. But all that starts tomorrow... I'm too tired tonight for the discipline required, and I need to double check my mission plan before starting.

Pretty much this... But I keep the old releases because there are a lot of good designs in there, and if the game has changed they still serve as inspiration. (Or warnings.)

Where is the redundancy in that scenario? One generation, and everything is over because you've no teachers. And you've got nobody in charge of making the stuff all the other guys need to do their jobs. Nor anyone in charge of managing all the systems. Or... well, I shouldn't have to draw you a diagram. There's a lot of specialties, and keeping them going requires a lot of people. This is a highly technical society, not log cabins out in the forest. The only reason such a colony could have 500 people is because it had an enormous technological society feeding it what it couldn't produce or provide locally. When that support is taken away... Are they? Under your scenario (no doctors) - one failure and you no longer have redundancy, you're one additional failure away from complete failure. Not a very good situation.

They had engineering drawings for the Nova (as a direct ascent to the Moon), and for the lander it carried (which made a direct landing on the Moon and a direct ascent back to Earth) too. That's not what flew though.

Precisely. And at the numbers of colonists quoted, and figuring in those too young to have entered the workforce (you're not going to have a modern technological society without education)... Losing one invaluable specialist, who is probably the only one of his kind in the colony, can be a pretty heavy blow. That's why the five figure populations I described above - there's a lot of specialties.

You get a brain tumor, you die. You get a serious concussion, you die. You suffer a fever that causes swelling of the brain, you die. You... well, you get the picture. And neurosurgeon isn't the occupational specialty.

The people I know who've thought deeply about this all think that the real bottleneck isn't genetics - it's occupational specialties. A colony of 500 might only need a neurosurgeon once every two years or so for example... where does he get his training and experience? Etc... etc... With sufficient and proper tech this can be hand waved away of course, but it's something to be aware of. (The numbers I've seen tossed about to avoid this bottleneck are in the five digit range.)

That brings up an interesting question... where does the airship dump it's excess heat?

On Falcon 9 cores? I don't think a Raptor can throttle that low, I don't think it can throttle at all. Even if it could, staged combustion engines have nasty startup transients.

The other engines gimbal to compensate. 1960's tech at worst. Then you have a Very Bad Day, a series of Solemn Ceremonies after which a lot of people get drunk and then have hangovers the next day. But frankly, you'd have to work pretty hard nowadays to have an engine so unreliable that there was any significant chance of that happening. It's much more likely that one of favorite anime girls will come to life and walk into my living room between the time I put the period on this sentence and hit "submit reply". EDIT: Dang, didn't happen. But seriously, the odds are extraordinarily low. Some things you just have to accept.

The President has about as much control over the Senate Launch System as you or I do. And about one ten thousandth of the desire to do anything about.

Honestly, I do pretty much all my plane change burns right after entering the target SOI, they're incredibly cheap out there and it gets the burn out of the way. This is especially important at Kerbin, Duna, and Jool where there are moons to worry about. (Especially at Duna.)

And the electronics that control those machines - what are they made of, and how are they replaced?

In other words, I was correct - not one of the failures of the N1 was linked to thrust imbalance.

Pretty much all of the space community is concerned only about the wagon - the rest has always been the "?????" step.

Carbon - and a whole bunch of other elements that make up the resin. Where do they get the other elements?

This. The only way a Martian colony functions as a "backup of humanity" is if it's a healthy and entirely self sufficient colony - something that has never really been tried, even on Earth, even back before the Industrial revolution. The challenges of setting up such a second civilization (because once it's self sufficient, it's not really a colony anymore) are immense and costly. Everyone babbles on about the rockets, but really rockets only rate a footnote in the appendix compared to all the other issues the space fanboys don't talk about because they aren't sexy rockets. And that's real issue here - the whole "colonize Mars" and "backup of humanity" are just figleaves to give an excuse for a discussion of rockets.

Um, no. None of the N-1 failures were caused by or linked to unbalanced thrust. The first vehicle was lost due a fire caused by ruptured fuel and oxidizer lines. The second due to fire caused by an explosion in a turbopump. The third due to aerodynamic effects. The fourth due to structural stress. At any rate, unexpected engine shutdown can happen with much fewer engines too - ask the flight controllers on SA-502. Or Apollo 13, where the S-II's center engine shut down early. (The Saturn V, when you look at the many failures due to POGO, was actually quite a problematic vehicle.) Or STS-51F.

Still plugging away on my Jool 5 challenge preps (I know you are all so tired of hearing that)... I was curious whether the Tylo/Vall lander could reach Bop or not. After Hyperediting a fueled lander core to Vall, I was quite surprised to find that not only could it reach and land on Bop - it could then return to the mothership without being refueled. On the actual mission, since the mothership is between Vall and Bop I'll probably make a pitstop there to top off the fuel tanks and give myself a little extra margin. I'm actually quite pleased with myself - I've now made one lander do triple duty. Some beauty shots, the lander on Bop and rendezvousing with a docking target in the mothership's planned orbit. Since the Jool 5 challenge requires a mission report, I started a thread in the Mission Reports forum detailing my prep work and explaining some of my decisions along the way. Stop by and take a look, comments and questions are welcome!

Update: 09/28/2016 All of which brings us to tonight's work, I was curious whether the Tylo/Vall lander could reach Bop or not. After Hyperediting a fueled lander core to Vall, I was quite surprised to find that not only could it reach and land on Bop - it could then return to the mothership without being refueled. On the actual mission, since the mothership is between Vall and Bop I'll probably make a pitstop there to top off the fuel tanks and give myself a little extra margin. I'm actually quite pleased with myself - I've now made one lander do triple duty. A beauty shot of the lander rendezvousing with a docking target in the planned mothership orbit.

I've been calling it a tug - but now it has a formal name, the Tanker/Transfer Vehicle. The design is a straightforward derivation of a vehicle I've built many times before. There are two key elements of it's design. First, the core LF/O tanks are X200-16's to match the lander tanks, which bumps the parts count a little but provides a handy "fuel gauge" when loading it at the mothership. The X200-8 will be loaded to give a little extra margin. Second, the radials (and their attached LV-N's) were positioned to place the loaded and dry centers of mass practically on top of each other. This made balancing the RCS a breeze, and even fully loaded the T/TV handles like a sports car. Looking at delta-V, I had another epiphany... If I used the LF capacity of the center tanks (and left the O tanks dry), then the T/TV has more than enough delta-V to return to Kerbin. This simplifies the design of the mothership, I won't need drop tanks. The current (untested) plan is for the T/TV to dock at the aft end of the mothership and provide a portion of the thrust.

The next task was designing the Vall lander. So once again, I started with an existing lander (the Tylo lander as it happened). That lander could handily reach the surface and return.... and that's when the epiphany hit me. I was already planning on adding a crew transfer vehicle or tug of some kind - what happened if I added refueling capacity? I quickly Hyperedited the core of the Tylo lander into Tylo orbit - and found that it could easily reach Vall. Thus the next elements of my architecture fell into place. The mothership's orbit would be between Vall and Tylo to minimize the delta-V required during the multiple trips back and forth. All landers would self ferry from the mothership to their destinations. The crew and landing fuel would then arrive via transfer vehicle. After the landing and return to orbit, the transfer vehicle would return the crew to the mothership. The Tylo lander would be refueled by the transfer vehicle when it picked up the crew, and self ferry to Vall. At Vall, the transfer vehicle would refuel the lander and transfer the landing crew. After the landing and return to orbit, the transfer vehicle would return the crew to the mothership. About this point, I made the first engineering mockup of the mothership's configuration with the two landers sitting on top of radial tanks. Surprisingly, this configuration flew quite well, the CoM was only mildly offset. (And that offset will be even smaller in the final mothership which will be much larger than this.) With the architecture beginning to fall into place, I returned to the Tylo lander (now the Tylo/Val lander) - since it needed to self ferry, a cruise stage seemed a natural addition. After re-fueling, the cruise stage would serve as a crasher stage - which meant I'd be able to land with the radials still attached (though practically empty of fuel) and avoid the problematic drop in t/w ratio of the first version. The original Tylo lander; The revised version with a cruise/crash stage: I was concerned about the weight of this version... but set that aside for the moment. Onward to designing the tug.